Hydraulically damped actuator for self-closing doors



Sept. 23, 1969 G. PRACHT 3,467,982

HYDRAULICALLY DAMPED ACTUATOR FOR SELF-CLOSING DOORS Filed March 10.1967 2 Sheets-She et 1 Gain/er PRAC/lf Sept. 23, 1969 PRACHT 3,467,982

HYDRAULICALLY DAMPED ACTUATOR FOR SELF-CLOSING DOORS Filed March 10,1967 2 Sheets-Sheet 2 V EN T 0R Gdmer Pram/77 United States Patent Int.Cl. 136st 3/06 US. Cl. 16-55 3 Claims ABSTRACT OF THE DISCLOSURE Thisinvention provides a hydraulically damped actuator for self-closingdoors. The actuator includes a bearing means supporting' a rotatableshaft which projects from a housing. A spring encircles the end of theshaft inside the housing to effect the closing of a door. A damper meansis located inside the said housing and includes a reciprocally movablepiston located in a cylinder which is disposed perpendicularly to theshaft axis. One end of the connecting rod is attached to the pistonwhile the other end of the connecting rod has a large open circular endslidably mounted over an eccentric member. A bearing means is providedto mount the eccentric member independently of the shaft. A door-closingarm is coupled to the eccentric member for effectively utilizing theactuator.

BACKGROUND OF THE INVENTION In hydraulically damped actuators forself-closing doors of the specified kind the piston of the damper isoperated by the shaft, so that the eccentric which operates theconnecting rod must be mounted on the bottom end of the shaft whichprojects from the shaft bearing. Since the shaft is subjected toconsiderable loads and must therefore be mounted in a bearing ofrelatively great length, the described form of construction of ahydraulically damped actuator for self-closing doors necessarilyrequires a housing of inconveniently great height.

SUMMARY OF THE INVENTION It is therefore the object of the presentinvention to overcome this drawback by providing a hydraulically dampedactuator for self-closing doors of the afore-described type which,compared with conventional actuators, is of much reduced height andwhich is also structurally much simpler.

For achieving this object the present invention consists in mounting theeccentric independently of the shaft and in directly coupling the sameto the door-closing arm, the door-closing spring embracing the end ofthe shaft inside the actuator housing directly below the shaft bearing.

The proposed separation of the eccentric from the shaft permits theeccentric to be located highed up in the housing, thereby fundamentallyaltering the disposition of the components in the available space infavor of a more compact form of construction of the actuator housing.The proposed removal of the eccentric into a higher position makes thefree projecting end of the shaft inside the housing available forexclusive cooperation with the doorclosing spring, and consequently theheight of the housing can be reduced. Moreover, the direct connection ofthe door-closing spring to the shaft eliminates the necessity ofproviding an entraining and pretensioning bush and of coupling thelatter to the door-closing arm. The proposed arrangement thusstructurally substantially simplifies the self-closing door actuator.Finally, the proposed arrangement permits the door-closing spring to bereadily exchanged through the open bottom of the actuator housingwithout requiring the door-closing arm to be first detached from theshaft as was hitherto necessary.

According to an important feature of the invention the closing arm andthe eccentric are coupled by a hub formed on the eccentric and adaptedon its end projecting from the housing to receive the fitting head ofthe closing arm in a push-on fit, whereas the coupling connectionbetween the door-closing arm and the rotatable shaft is established by apush-in coupling member which nonrotatably engages the end of the shaftwhich projects from the housing as well as the fitting head of thedoorclosing arm.

BRIEF DESCRIPTION OF DRAWINGS An embodiment of the invention will now bedescribed by way of example and with reference to the accompanyingdrawing, in which:

FIG. 1 is a longitudinal section through a self-closing door actuatoraccording to the invention;

FIG. 2 is a section taken on the line II-II of FIG. 1;

FIG. 3 is a view of the eccentric and its hub;

FIG. 4 is a section taken on line IV-IV of FIG. 1, and

FIG. 5 is a sectional bottom view of the actuator as shown in FIG. 1.

DESCRIPTION OF SPECIFIC EMBODIMENT With reference now to the drawing, 1is the actuator housing, 2 is the door-closing shaft which works in theactuator housing 1 in a journal bearing 3 formed by a steel bush, 4 isthe door-closing arm, 5 is the closing spring and 6 is a preferablysteel cylinder liner firmly fitted into the actuator housing 1 andtogether with a piston 7 forming the damping device. The outer end ofthe cylinder liner 6 is sealed by a screw plug 8. 9 is a cylinder corewhich axially traverses the piston 7 and which is secured therein bythreads engaging the piston interior. The projecting threaded end of thecore 9 carries a counternut 10 which is tightened against the end faceof the piston 7. 11 is an eccentric mounted on the journal bearing 3 andslidably supported by an intermediate platform (not numbered) inside theactuator housing. The eccentric 11 cooperates with a connecting rod 12of which the big end embraces the eccentric, whereas the other end workson a gudgeon pin 13 mounted on the periphery of the projecting end ofthe core 9 of the piston 7. The eccentric 11 is formed with a collar orhub 14 which projects from the actuator housing 1 to the outside. Thehub 14 has an internal shoulder which bears on the end of the journalbearing 3, whereas the end of the hub projecting from the housing 1embraces the shaft 2. Externally, the projecting end of the hub 14 has asquare cross section embraced by the correspondingly shaped fitting head15 of the doorclosing arm 4. The shaft 2 which is encircled by a splitring 16 resting on the end of the hub 14 of the eccentric 11 is providedwith a reduced section square end which passes through the fitting head15 of the closing arm 4. 17 is -a coupling member which fits over thereduced square end of the shaft 2 for common rotation therewith andwhich also engages and fits into the interior of the fitting head 15 ofthe closing arm 4, thereby rigidly coupling together the closing arm 4and the shaft 2 and hence the eccentric 11. The coupling member 17 islocated on the reduced end of the shaft 2 by a split ring 18. 19 is anassembly opening in the actuator housing 1 closable by a screw cover 20.The bottom end of the shaft 2 projecting from the journal bearing 3 isformed with a circular enlargement 21 which is encircled by the closingspring 5 located in a spring housing 22. The spring 5 may be mounted inthe actuator housing 1 in any manner known in the prior art. In thisspecific embodiment the inner claw end 25 of the spring 5 engages anaxial slot 26 in the enlargement 21 of the shaft 2. The outer spring end23 engages a recess 24 located in the actuator housing l-in a mannerwell known in the prior art. In conventional manner the actuator housing1 is enclosed by a cow] not shown in the drawing.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respect as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description.

I claim:

1. A hydraulically damped actuator for self-closing doors comprising, incombination,

(a) a bearing means suporting a rotatable shaft which projects from ahousing,

(b) means mounting a spring which encircles the end of a shaft insidethe housing to effect the closing of a door,

(c) a damper means including a reciprocally movable piston located in acylinder which is disposed perpendicularly to the shaft axis,

(d) means connecting one end of a rod to the piston,

(e) the other end of the rod having a large open, circu lar end slidablymounted over an eccentric member,

(f) bearing means mounting said eccentric member independently of theshaft,

(g) said closing spring being located below the said bearing means, anda (h) means coupling a door-closing arm to the eccentric member.

2. An actuator for self-closing doors as claimed in claim 1, wherein theclosing arrnand the eccentric are coupled by a hub formed on theeccentric and adapted on its end projecting from the housing to receivethe fitting head of the closing arm in a push-on fit, whereas thecoupling connection between the door-closing arm and the shaft isestablished by a push-in coupling'rnember which engages the end of theshaft projecting from'the housing as well as the fitting head of thedoor-closing arm.

3. An actuator for self-closing doors as claimed in claim 1, wherein thebottom end of the shaft below the bearing has a circular enlargementembraced by the doorclosing spring.

References Cited UNITED STATES PATENTS 3,210,797 10/1965 Heinitz et a1.16-59 BOBBY R. GAY, Primary Examiner JAMES KOHNEN, Assistant ExaminerUNITED STATES PATENT OFFICE CERTIFICATE *OF CORRECTION Patent No.3,467,982 September 25, 1969 G'u'nter Pracht It is certified that errorappears in the above identified patent and that said Letters Patent arehereby corrected as shown below:

In the heading to the printed specification, lines 4 to 6, "assignor toC. Eisen Grossmannund Stahlwerk AG. Solingen- Wald, Germany, a firm"should read assignor to C. Grossmann Eisenund Stahlwerk AG.Solingen-Wald, Germany, a firm Signed and sealed this 10th day ofNovember 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

